The packaging of integrated circuit chips is important to the design and manufacture of electronic systems for a variety of reasons. A chip is generally too small and delicate to handle without suitable protection during the manufacture of equipment incorporating the chip. Accordingly, a carrier package is often used to protect the chip against mechanical damage during such operations as electrical testing, "burn in", marking, shipping and the like, as well as to protect against damage arising from static charges or leakage currents. The carrier package also facilitates the mounting of the chips on circuit boards.
A molded carrier ring (MCR) package is a particularly useful package for chips with a large pin count and thus fine pitch (i.e., a spacing on the order of 0.8 mm or less between adjacent leads on the chip). Unlike the leads on other carrier packages which typically are accessible from the top or bottom of the package, the leads on the MCR package are accessed from the side through conductor pads which are "low-set", i.e., they do not protrude appreciably from the frame.
A test contactor is a device that establishes electrical connections between the conductors of a chip carrier package and test circuitry for performing tests of the chip. During testing, it is usually necessary for the contactor to make simultaneous contact with all of the chip carrier conductors for complete circuit checking. However, because of the small size of the MCR conductor pads and the close spacing of those pads, contact strips in the contactor must be precisely applied to the pads to ensure accurate testing of the chip.